1. Field
The following description relates to a method and an apparatus configured to perform a soft demapping in a rotated quadrature amplitude modulation (QAM) based communication system.
2. Description of Related Art
A wireless communication system and a broadcasting system may use a rotated quadrature amplitude modulation (QAM) transmission technology. For example, a digital video broadcasting (DVB) standard, for example, a digital video broadcasting-second generation terrestrial (DVB-T2) standard, requires use of the rotated QAM.
During wireless signal reception and transmission, a wireless channel may experience fading in a wireless communication system. The fading refers to attenuation of a wireless signal during transmission of the wireless signal. To combat such fading-related issues, a diversity method may be employed. For example, the diversity method includes spatial diversity and frequency diversity.
Also, to prevent fading, a signal-space diversity method is used by a great number of technologies, including the DVB-T2 standard. As an example, a rotated QAM constellation may be used to implement the signal-space diversity method.
However, when a transmitter uses the rotated QAM, a receiver would be configured to be complex and would be required to perform a soft demapping. Accordingly, research is continuously conducted reduce structural and functional complexity required to perform the soft demapping at the receiver.